From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8C5DFC48297 for ; Tue, 6 Feb 2024 22:29:28 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rXTwF-0002uq-BF; Tue, 06 Feb 2024 17:29:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rXTw9-0002ub-Jh for qemu-devel@nongnu.org; Tue, 06 Feb 2024 17:29:06 -0500 Received: from mail-pj1-x1034.google.com ([2607:f8b0:4864:20::1034]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1rXTw6-0005th-AU for qemu-devel@nongnu.org; Tue, 06 Feb 2024 17:29:03 -0500 Received: by mail-pj1-x1034.google.com with SMTP id 98e67ed59e1d1-2907a17fa34so5257645a91.1 for ; Tue, 06 Feb 2024 14:29:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1707258540; x=1707863340; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=h2ftN6EYno3st+TquCdN+VzNqndBsQ2s0pMELCUm/sU=; b=qri47zmh1pKsHd9Nv3gFzwbG2PsWti8gMeLSsyyiDbeeC4Jbxfc8Z5aOsDS5Gtflnq hLYZ7ReXTnu9dnl2jSOsmtU3OqiHt5U4m38t2PhmEdq6K5yF6cd7szvLo4/i9qpPwADR /g/0Zh/zM7brdqii1he620s3TvsCS8g/52HpN5SDAM8d0KgKvhW0t7otH2tMGSL8uKp6 AHPjjaQU/fmdq6TxOM4Z9JMlxP4+0lRirxPkF62wkcXIGeV2BC7wEoAQVvPlY/y3SMVl 8n2A4VZReNO384/3nqYHt/xR7gk93iWwCtARijkVNuoToY5yExhiJrh+VCbQGc3lBsIo kdMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707258540; x=1707863340; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=h2ftN6EYno3st+TquCdN+VzNqndBsQ2s0pMELCUm/sU=; b=EWYkqvso0PW4JIVhTiKUpC4gFixTGeZz4lSs27PZJFBN9pTIihZImdSr7ag5Z372k1 KwJHovpbEf9JuGitHqHZMpgJTyfIeLkmbc2Lkk/NnxKkifP+WgwKQa+YwlFZVzeDOnUw Yk1kiOfUedFUA/DIHki1EGYhK+3dbraFsYf9na25IpCX5uyFUOtNifqzC90RFNwA4AiK eNfz2LYO+0o6xgnPyYd5TOJTm3VmTkbQ4zSpKuLPl18qAlUs7F0jnOv+frOxsva2paFK EuVn4srVfYSfb6G1OVO/21jdHki+Mms+BcEa8wdI6oAlIYP7j0njhL/2hWjDKnpjnJgJ 2MPw== X-Gm-Message-State: AOJu0YwxSRdlEe2vCjbvocBW+hxGTYEhaRjgOhozp11O93fqIqkvOczf i34btUPhf7jrZDVsfHB08JWz4g+LypINV7RJSbt97o06c7wqq+845+scvbDNVv0= X-Google-Smtp-Source: AGHT+IFjrxeE8AyMh0nlSoN1Gg4vBJMqvyNROqakI3fFoNbjr7WUAhNsMov0jzxji+Pu+MWccKCC4w== X-Received: by 2002:a17:90a:c683:b0:296:865d:e0c0 with SMTP id n3-20020a17090ac68300b00296865de0c0mr991397pjt.45.1707258533716; Tue, 06 Feb 2024 14:28:53 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCUcgk1ab06WhF1P27YMhgxt0072hCj4dWBtM6Th8/gLL1otu5XH+zmAHVIElkGmSDrNAzGi19JoV57iz3me+S9aB8HVtD/7hxIhuZBtrWfyTLlX6c0EFFJTB2A= Received: from [192.168.0.100] ([43.252.112.200]) by smtp.gmail.com with ESMTPSA id sy7-20020a17090b2d0700b00296ca138c96sm31105pjb.26.2024.02.06.14.28.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 06 Feb 2024 14:28:53 -0800 (PST) Message-ID: <2263455d-7f03-48fb-ab0b-f2a6100edcc8@linaro.org> Date: Wed, 7 Feb 2024 08:28:48 +1000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/6] util/bufferiszero: remove AVX512 variant Content-Language: en-US To: Alexander Monakov , qemu-devel@nongnu.org Cc: Mikhail Romanov , Paolo Bonzini References: <20240206204809.9859-1-amonakov@ispras.ru> <20240206204809.9859-4-amonakov@ispras.ru> From: Richard Henderson In-Reply-To: <20240206204809.9859-4-amonakov@ispras.ru> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::1034; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x1034.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 2/7/24 06:48, Alexander Monakov wrote: > Thanks to early checks in the inline buffer_is_zero wrapper, the SIMD > routines are invoked much more rarely in normal use when most buffers > are non-zero. This makes use of AVX512 unprofitable, as it incurs extra > frequency and voltage transition periods during which the CPU operates > at reduced performance, as described in > https://travisdowns.github.io/blog/2020/01/17/avxfreq1.html > > Signed-off-by: Mikhail Romanov > Signed-off-by: Alexander Monakov > --- > util/bufferiszero.c | 36 ++---------------------------------- > 1 file changed, 2 insertions(+), 34 deletions(-) Reviewed-by: Richard Henderson Although I think this patch should be ordered second. r~